Heat engine



March 1 1927' R. w. DAVENPORT HEAT ENGINE Original Filed Nov. 29, 1922 FIG. 2

INVENTO Patented Mar. 1, 1927 UNITED STATES PATENT OFFICE.

BANSOM W. DAVENPORT, OF DETROIT, MICHIGAN, ASSIGNOR TO CHICAGO PNEU- MATIC TOOL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

HEAT ENGINE.

HEISSUED Original application filed November 29, 1922, Serial No. 603,998. Divided and this application filed April 25, 1924. Serial No. 708,936.

My invention consists in improvements in heat engines and is particularly adapted to employ in certain thermodynamic operations the novel working substance described and claimed in my co-pending application filed Nov. 29, 1922, Ser. No. 603,998 of which original application the present application is a dlVlSlOIl; and for performing upon the said novel working fluid such heat-transforming operations as are described and claimed in my application filed June 21, 1922, Ser. No. 570,015 also copending. V

This present and the two aforesaid inventions constitute a closely related series of inventions.

Besides the above mentioned objects, the present invention rovides means for utilizing the peculiar advantages inherent in the 0 aforesaid inventions, and applying them to the practical cooling of refrigerators. Other objects of my invention will appear hereinafter.

All refrigerating apparatus of the comression type hitherto known or used falls into one of two perfectly distinct and separate classes, i. e., the va or-compression class or compressor-con enser-expander type, and the cold air type or compressorcooler-expansion motor class. This separation is but the natural result of the essential and basic differences between the liquidvapor refrigerant-s used in the former, and the ideal gas refrigerants used in the latter class of apparatus. It is emphasized that in the va or compression type of heat engine the re rigerating effect is obtained not by expansion but by vaporization of liquid at constant temperature and pressure, which liquid is fed as liquid, and without expansion, through a throttle valve loosely called the expansion valve, whereas in the coldair machine the entire refrigerating effect is obtained by expanding air or other gas (not vapor) in an expansion motor.

y improved heat engine differs from both the above described types of heat engine in that I employ both an expansion device and a boiler or vaporizing element in novel combination with a compressor and a condenser, and in other respects herein after set forth, and is depicted in certain representative forms in the accompanying drawings.

Fig. 1 is a front elevation-section of a form of my invention including the refrigerator.

Fig. 2 is a side view of parts of same.

In the form shown in Figs. 1 and 2, in which figures like parts have like numerals, my invention may be described as follows: 1 is an electric motor geared to a compressor 2 which discharges into condenser 3. The evaporator comprises the headers 4. and 5 connected by the ribbon-shaped duct 6, with the separator 7 forming the outlet and nozzle 8 the inlet. The outlet 7 is connected to the intake of the pump 2 by the pipe 9, and the inlet nozzle 8 is connected to the condenser 3 by the pipe 10 which is placed inside the pipe 9 to form a heat exchanger therewith.

The insulated refrigerator cabinet 11 contains compartments 12 and 13 each of which may also be insulated, and the evaporator traverses all three as shown. Shelves 14 to 17 may be used to carry the articles to be cooled.

This embodiment of my invention operates substantially as follows: after chargin the system with a proper quantity of a suitable working substance of the type"be fore mentioned, with a supply of the liquid component in the evaporator as shown, and air and vapor in the rest of the space, the

motor 1 is started and the com ressor 2 compels the circulation of the wor 'ng substance. The total pressure in the evaporator 4-5-45 falls while the total pressure in the condenser 3 rises, thus causing the liquid in the evaporator to evaporate and absorb heat from the refrigerator, and the vapor in the condenser to liquefy and eject heat to any suitable cooling medium as air or water (not shown). The expander 8 offers suitable resistance to the flow of gas vapor and liquid fed to it in contiguous streams through duct 10 from the condenser, thus maintaining suitable difference in pressure between condenser and evaporator. The li uid in the evaporator is caused to emul- S1 with the gas and vapor b the action and this I d to be of great advantage in facilitating evaporation and rapid cooling of liquids of relatively low va or tension, such as alcohol etc., which, in the old vapor compression types of heat engine, lacking my combination of of the expander 8,

expander and evaporator, lie inert and unable to produce practical refrigerating effeet. It is to be understood that the ind cated gauge suction or back pressure 13 hi'rher than that corresponding with the temperature of the liquid refrigerant, which temperature is limited only by the partial vapor pressure effective at a given time and lace. p By the combination with the expander, of my improved emulseur-evaporator, I am enabled to derive the further advantage of operating at a plurality of refrigerating temperatures, since I find that the lower header 4 tends to be colder than the upper header 5, when circulation between them is restricted by any suitable means, such as the fiattened or ribbon-shaped duct 6. I may apply this peculiar advantage in any desired way as, for example, by combining my improved evaporator with suitably insulated chambers 12 and 13 so disposed that the lower one 12 is colder than the others, while chamber 13 a little higher up and nearer header 5 will warmer and the main chamber or cabinet itself may be still milder in tern erature. By this arrangement water may be rozen in ice-chamber 12, raw meats, milk, butter etc. may be kept at temperatures around that of melting ice in chamber 13, while the main compartments formed by the shelves 15, 16, 17 may be kept at, for instance, 50 degrees F. for general articles such as cooked foods and raw vegetables. Since the bulk of the heat transfer occurs at this relatively high temperature, I am enabled to procure much higher economy than was possible where the refrigerant must be evaporated at a temperature and pressure low enough to make ice, while the cabinet itself was operated at a lower temperature than is real y needed, as was necessarily the case with all former refrigerators, cooled by mechanical means.

Besides the obvious advantages of my invention, other advantages inhere such as the fact that with the aid of my improved refrigerant before mentioned, my apparatus may be made self-re ulating. For example, using carbon tetrachloride as the liquid component of my working substance. the freezing point of which is around zero F., the nozzle 8 freezes up at this temperature thus limiting the temperature in all compartments of the refrigerator and simultaneously unloading the compressor so that the power required is practically as low as that with blanked intake. The costly and troublesome thermostat always a vital part of the former automatic refrigerating machines is, by virtue of the cooperation of my improved refrigerant with the present invention, done awa with. 1

Likewise the trouble-making expansion valve which, in the old systems, was always required in order to maintain the liquid seal essential between the condenser and expander, is, by my invention, dispensed with along with the seal.

The reversibility of the heat engine above described may be extraordinarily high owing to the temperature gradient in the refrigerator.

I claim:

1. Refrigerating apparatus utilizing as a refrigerant a physical mixture of a liquid and a gas inert to and insoluble in said liquid comprising a compressor, means to operate said compressor, a refrigerating element for containing the liquid refrigerant, a continuously open nozzle opening into said element, a condenser, ducts connecting said compressor to said element and to said condenser re spectively, and a duct through which contiguous streams of li uid and gas pass from said condenser to said nozzle.

2. Refrigerating apparatus of the closed cycle type comprising a plurality of refrigerating chambers, vessels containing an evaporable liquid disposed in thermal relation with said chambers, ducts arranged to connectsaid vessels to form a series, means including a. nozzle for expanding into the first vessel of said series a stream of mixed gas and vapor, means for removing gas and vapor from the last vemel of the series to provide the stream forced into said first vessel, and means in said cycle for maintaining the aforesaid liquid in said vessels.

3. In a heat engine of the compressor-condenser-evaporator type utilizing as a working substance a li uid and a gas substantially inert and insoluble in the liquid, a compressor, a condenser, and an evaporator, said evaporator for containing a body of said liquid, a De Laval nozzle ar ranged to dischar e into said evaporator, and a pipe connecting saidnozzle with said condenser, said nozzle area being so proportioned as to pass contiguously both the liquid and the gaseous components of the refrigerant.

4. In refrigerating apparatus for utilizing a refrigerant having liquid and gaseous components, an evaporator for containing the liquid component of the refrigerant, means continuously to force the gaseous component of the refrigerant in a closed cycle through the liquid component in said evaporator, and means for wit drawing heat from said gaseous component at one point in said cycle.

5. Refrigerating apparatus for utilizing a refrigerant havingliquid and gaseous components comprising an evaporator for containing the liquid component of the refrigerant, means continuously to withdraw the gaseous component and the vapor of the refrigerantfrom the eve orator, cool said mixture and liquefy the re rigerant and return said mixed tor.

liquid and gas to the bottom of the evapora 6. Refrigerating apparatus for utilizing a refrigerant having liquid and us components comprising a heat absorbing element forz-eoptaining the liquid component of the'refrig'erant, a pump withdrawm the gaseous component of the refrigerant om the top of said element, aheat ejecting device through which said gaseous component is forced b said pump, and a duct leading from said evice to the base of said-element and providing a restricted opening so proportioned as to pass the mingled condensed and non-condensible components of the circulated refrigerant which expand directly into and up through the liquid in said element.

7. Refrigerating apparatus for utilizing a refrigerant having liquid and gaseous component-s comprising a heat absorbing element for containing the liquid component of the refrigerant, a pump withdrawing the gaseous component of the refrigerant from the top ofsaid element, a heat ejecting device through which said gaseouscomponent is forced by said pump, and a duct leading from said device to the base of said element and terminating in a De Laval nozzle, the nozzle area being so proportioned as to pass continuously and in contiguity both the condensed and the non-condensible products of said heat ejecting device.

8. Refrigerating apparatus for utilizing a refrigerant having liquid and gaseous components comprising a heat absorbing element for containing the liquid component of the refrigerant, a pump withdrawing the gaseous component of the refrigerant from the top of said element, a heat ejecting device through which said gaseous component is forced by said pump, a duct leading from said device to the base of said element and providing a restricted opening of such size as to pass the mingled condensed and noncon'densible components of the circulated refrigerant directly into the liquid in said element, and means for precooling the circulated refrigerant intermediate said device and said element. 7

9. Refrigerating apparatus for utilizing a refrigerant having liquid and gaseous components comprising a heat absorbing element for containing the liquid component of the refrigerant, a pump withdrawing the gaseous component of the refrigerant from the top of said element, a heat ejecting device through which said gaseous component is forced by said pump, and a duct leading from said device to the base of said element and providing a restricted opening of such size as to pass the mingled condensed and non-conde'nsable components of the circulated refrigerant directly into the liquid in said element, said duct bein brought into thermal cont-act with the re atively colder gaseous component being withdrawn from ithe'top of said element by said pump thereby to precool the circulated refrigerant.

10. Refrigerating apparatus for utilizing a refrigerant having liquid and gaseous components comprising a heat absorbing element for containing the liquid component of the refrigerant, a pump withdrawing the gaseous component of the refrigerant from the top of said element, a heat ejecting device through which said gaseous component is forced b said pump, and a duct leading from said and providing a restricted opening of such size as to pass the mingled condensed and non-condensable components of the circulated refrigerant directly into the liquid in said element, a portion of said duct being disposed within the top of said element thereby to precool the circulated refrigerant.

1.1. In refrigerating apparatus for utilizing as a refrigerant a physical mixture of a liquid and a gas substantially inert to and insoluble in said liquid, a refri crating element for containing the liquir? portion of the refrigerant, and means producing a rapid ebullition of said liquid com rising members forming a closed cycle t rough which the gaseous portion of the refrigerant is circulated and including a continuousl open port in said element through which said gaseous component is forced to bubble up through said liquid component.

12. In refrigerating apparatus for utilizing as a refrigerant a physical mixture of a liquid and a gas substantially inert to and insoluble in said liquid, a refrigeratin element for containing a body of the liquid, means producing a rapid ebullition of said liquid body including a compressor arranged to withdraw the gas and the vapor of the liquid from said element and return the same under pressure to said element adjacent the bottom thereof, and means for removing heat from said gas-vapor stream before it is returned to said element.

13. In refrigerating apparatus for utilizing as a refrigerant, a physical mixture of a liquid and a gas substantially inert to and insoluble in said liquid, a refrigerating element for containing a body of the liquid, a compressor arranged to withdraw the gas and the vapor of the liquid from said element, means for removing heat from said gas-vapor stream, and means for returning said gas-vapor stream under pressure to said element comprising a continuously open port in said element.

14. In refrigerating apparatus for utilizing as a refrigerant, a physical mixture of a liquid and a gas substantially inert to and insoluble in said liquid, a refrigerating element for containing a body of the liquid, .a compressor arranged to withdraw the gas and the vapor of the liquid from said eleevice to the base of said element ment, means for condensing at least a part of said vapor, means for reoooli said gasvapor-liquid stream an means or returning said gas-vapor-liquid stream under pres sure to said element comprising a continuously open port in said element.

15. A refrigerator having insulated walls and an elongate refrigerating element verti call disposed therein, and means causing sai element to absorb heat from said refrigerator at difierent tem ratures at vertical- 1y spaced points thereo 16. A refrigerator having insulated walls and an elongate refrigerating element vertically disposed therein, and means causing said element to absorb heat from said refrigerator at upwardly s aced ints on said element at progressive y hig er temperatures.

17. A refrigerator having at least three separate heat insulated compartments and asingle heat absorbing element in thermal contact with the interior of all said compartments, said compartments and said element being so arranged that heat is removed from said compartment at diflerent tem i part1 enclosing said element and maintained b y the latter at progressively higher temperature. 1

19. A refrigerator having heat insulated walls. providing an interior space to be cooled, a compartment in the bottom of said space to be maintained below freezing, a compartment above said first named compartment to be maintained at a temperature slightly above freezing, the remainder of the space being arranged to be maintained at asomewhat h' her temrature and a single heat absor i unit aving parts in thermal contact wit the interior of each of said compartments.

RANSOM W. DAVENPORT.

at a temperature 

